In a small lab in Strasbourg, the air is being turned into fuel. Aerleum, a French climate-tech startup spun out of the Marble venture studio, has taken a $6 million seed round to prove its core thesis: that capturing carbon dioxide and converting it into a usable fuel can be done in one integrated step, and that this process can eventually compete on price with fossil-derived methanol [EU-Startups, Oct 2024]. The company’s target is the maritime, heavy transport, and chemical industries, sectors where electrification is a non-starter and green hydrogen is a logistical puzzle. Their proposed solution is a bifunctional material that acts as both a sponge and a catalyst, promising to cut the energy penalty of conventional carbon capture and utilization by about 30% [Third Derivative, 2024].
The Single-Step Wedge
The conventional path to e-methanol involves two distinct, energy-hungry stages. First, you capture CO2, typically using a liquid solvent or solid sorbent that requires significant heat to release the captured gas. Then, you feed that purified CO2, along with green hydrogen, into a separate reactor for catalytic conversion. Aerleum’s proposed wedge is to collapse these stages. Their proprietary material is designed to grab CO2 directly from ambient air or a flue stream and immediately begin converting it, all within the same reactor vessel [Third Derivative, 2024].
From Lab Bench to Pre-Industrial Module
So far, the process works at benchtop scale. The company has successfully produced e-methanol from atmospheric CO2 in the lab [CB Insights, ~Oct 2025]. The seed funding, led by 360 Capital, HTGF, and Bpifrance with participation from Norrsken and Marble, is earmarked for the critical next step: building a pre-industrial module [EU-Startups, Oct 2024]. This unit is designed to produce 30 tons of methanol per year, a scale that moves from chemistry experiment to engineering prototype. The founding team, Steven Bardey (CTO) and Sébastien Fiedorow (CEO), brings a classic deeptech pairing: Bardey holds a PhD in the physical chemistry of materials from the University of Strasbourg, while Fiedorow previously worked at Bpifrance and within the deeptech ecosystem [Steven Bardey Crunchbase Person Profile, 2026] [RocketReach, 2026].
The Competitive Field and the Scale Mountain
| Company | Primary Focus | Notable Differentiator |
|---|---|---|
| Aerleum | Integrated capture & conversion to e-methanol | Bifunctional material for single-step process |
| ReCarbon | CO2 conversion to syngas | Plasma catalysis technology |
| Kvasir Technologies | CO2 to methanol | Fermentation-based biological process |
| Ammobia | CO2 to ammonia | Electrochemical synthesis |
Aerleum’s integrated approach is its sharpest differentiator, but also its tallest mountain. The technology must prove it can maintain efficiency and material integrity at the 30-ton module scale, and then again at the thousand-ton demonstration plant scale. The five-to-six year timeline to hit a target cost of $500 per ton is aggressive and hinges on continuous efficiency gains and access to cheap, renewable electricity [Third Derivative, 2024]. Furthermore, the market must materialize. Shipping giants and chemical companies are signaling demand for green methanol, but firm offtake agreements for a pre-revenue startup’s output are the truest validation, and none have been announced.